JPS6281508A - Optical 3-dimensional position measuring apparatus - Google Patents

Abstract

PURPOSE:To make a measuring action undisturbed by an action, etc. of a specimen, by measuring a 3-dimensional position of a space travelling body by an optically non-contacting method. CONSTITUTION:A light receiving element 14 representing an image of a light source 5 draws out a signal indicating the image position and provides it to an arithmetic operation means 8. The means 8, based upon this signal, allows an action of a supporting means that supports an optical detector 17 (2-dimensional position detector) free to displace respectively with respect to mutually intersecting 2 axes and drives the optical detecting means 17 and an image of the source 5 is developed in the specified position of a light receiving plane 19. This displacement is detected as a position on the 2 above mentioned shafts by the position detecting means 17. Signals representing each position on 2 above-mentioned axes from the position detecting means 14 is given to the means 8, where an arithmetic operation is conducted on a signal from light receiving element 14 and position detecting means 17 and a 3-dimensional position of the light source 5 is calculated.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to an apparatus for tracking and measuring the three-dimensional position of an object to be measured, such as a robot arm, which moves at a high speed in space.

BACKGROUND ART Conventionally, as a measuring device for the three-dimensional position of an object moving in space, such as a robot's arm, there is a measuring device that calculates the three-dimensional position of an object that moves in space by performing coordinate transformation calculations from the output values of a circular angle detector attached to each internodal portion.

■Measuring device that measures by directly applying a direct-acting potentiometer to the point to be measured from three directions.

■Attach a light emitting diode to the area to be measured and transmit the light to the
There is a measurement device that observes from two directions using two cameras with built-in dimensional light spot position detectors and performs measurements based on the principle of triangulation.

Problems to be Solved by the Invention Each of the conventional measuring devices described above has the following drawbacks.

Measurement device ■ uses indirect calculations, so the reliability of the calculation results is low due to errors in the robot arm's height and distance between joints.Measuring device -■ has the advantage of being able to measure directly. However, the distance measurement range is relatively short, and since it is a contact type, it puts a load on the object to be measured and is inconvenient because the settings are complicated. Measuring device (2) can perform non-contact measurements, but since it has two fixed cameras, it cannot be measured if the object to be measured is out of the camera's field of view, and the distance measurement range is relatively narrow.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems and provide an apparatus that can measure the three-dimensional position of an object moving in space over a wide range in a non-contact manner with high precision.

Means for Solving the Problems The present invention provides a light source attached to an object to be measured and an optical detection means, wherein an image of the light source is formed and a signal representing the imaged position is derived.
such an optical detection means including a dimensional light-receiving element, an optical system that is provided integrally with the light-receiving element and forms an image of the light source on the light-receiving surface of the light-receiving element; means for movably supporting the two pongees to be moved; means for detecting each position of the optical detection means on the two axes; and driving the optical detection means by the support means based on the output signal of the light receiving element. a first calculating means for forming an image of the light source on a predetermined position on a light receiving surface; and a second calculating means for calculating a three-dimensional position of the light source based on the outputs of the light receiving element and the position detecting means. An optical three-dimensional position measuring device is characterized in that it includes:

Operation Light from a light source attached to the object to be measured forms an image on the light-receiving surface of the light-receiving element via the optical system of the optical detection means. The light-receiving element on which the image of the light source is formed derives a signal representing the image-forming position and supplies it to the first calculation means and the second calculation means. Based on this signal, the first calculation means operates supporting means that displaceably supports the optical detection means with respect to two mutually intersecting wheels, and drives the optical detection means to detect the image of the light source. The image is formed at a predetermined position on the light receiving surface. This displacement is detected by the position detection means.
It is detected as a position above the two wheels. Signals representing each position on the two wheels from the position detection means are given to the second calculation means. The second calculation means calculates the three-dimensional position of the light source by processing the signals from the light receiving element and the position detection means.

Therefore, the position measuring device according to the present invention measures the three-dimensional position of an object to be measured without contacting the object to be measured,
Further, this measurement operation is performed by tracking the object to be measured.

Therefore, such a measurement operation can be performed over a relatively wide range in the space in which the object to be measured is placed, and does not cause any impediments to the movement of the object to be measured.
Accuracy of measurement can be ensured. Furthermore, by improving the detection performance of the light receiving element and the position detecting means, the accuracy of measuring the three-dimensional position of the object to be measured can be significantly improved.

Embodiment FIG. 1 is a system diagram illustrating the configuration of an embodiment of the present invention. With reference to FIG. 1, an optical three-dimensional position measuring device (hereinafter abbreviated as measuring device) 1 and its related configuration will be described. A light source 5 realized by, for example, a light emitting diode is attached to a measurement point 4 such as an arm 3 of a robot 2 which is an object to be measured and moves at high speed in space.

For example, two optical devices 6.7, which are optical detection means, are installed at a distance from the robot 2.

The outputs of the optical devices 6 and 7 are given to a calculation device 8, which is a second calculation means, and calculates the three-dimensional position of the light source 5, as will be described later.

FIG. 2 is a simplified perspective view of the optical device 6.

The optical *1fi6 has a so-called gimbal structure consisting of two axes, a rotation axis 9 and an elevation axis 10. In other words, the pivot axis 9 is
Angularly displaced in the direction of arrows Al and A2 by the motor 11,
An elevation shaft 10 is provided on a frame 12 that is integrally connected to the rotation shaft 9 so as to be freely angularly displaceable.

The frame 12 includes mutually orthogonal lateral support members 36, 37 and longitudinal support members 38, 39, and is generally rectangular in shape. Further, the rotation axis 9 is parallel to the vertical support members 38, 39, and is connected to the midpoint of the horizontal support members 3f3, 37, and the elevation axis 1
0 is parallel to the horizontal support members 36 and 37 and is parallel to the vertical support member 38
．． 39 so as to be freely angularly displaceable. The elevation axis 10 is moved by the motor 13 to the arrow A3. When angularly displaced in the A4 direction, the optical tube 14 fixed to the elevation axis 10 also moves in the direction of arrow A3.
Angular displacement in the A4 direction. Therefore, the thin line of the optical barrel 14 can point in any direction.

Also, a rotation axis 9 and an elevation axis 10 by motors 11 and 13.
The angular displacements θ, θI2 in the directions of the arrows A 1 , A 2 :A 3 , A 4 are determined by the angle detector 1, which is a position detecting means realized by, for example, an encoder.
5.16, it is detected with high accuracy.

FIG. 3 is a perspective view of the optical barrel 14. The optical tube 14 incorporates a two-dimensional position detector 17, which is a light-receiving element and has a specific configuration as will be described later, and a lens 18, which is an optical system, is placed on the light-receiving surface 19 of the two-dimensional position detector 17. Collects the light A5 from the

The configuration regarding the optical device 6 as described above is the same in the optical device 7 shown in FIG. Reference numbers 9 to 19 are shown with a subscript a,
Rotating shaft 9a and elevation 1 by motors 11a and 13g
Angular displacement amount θ2 of 0a. .

O22 is detected with high precision by a rotation angle detector 15a=16a which is also a position detection means realized by an encoder or the like. The support means is constituted by including the pivot axis 9.9a and the elevation axis 10=10a.
Rotation angle detectors 15, 16; 15a.

16a constitutes a position detection means.

FIG. 4 is a perspective view illustrating the present invention in detail.

The principle of the present invention will be explained with reference to Figure #S2 and Figure @4. The optical axis 21 of the optical device 6 includes the rotation axis 9 and the elevation axis 1 which are realized as a non-pulsating structure as described above.
It is configured to pass through the intersection point R1 of the zero axes. The optical axis 22 of the optical device 17 is configured to pass through the intersection R2 of the axes of the rotation axis 9a and the elevation axis 10a, which also form a resympal structure.

That is, regarding these optical devices 6.7, an absolute coordinate system Σ consisting of mutually orthogonal X-sleeves, Y-sleeves, and Z-sleeves. Set. This absolute coordinate system Σ. is set so that the X wheel passes through the intersection R7 of the optical device 6 and the intersection R2 of the optical device 7, and the Z axis is parallel to the rotation axes 9, 9&. Further, the elevation axes 10 and 10a are within the XY plane.

Regarding the two-dimensional position detector 17 built into the optical device 6, three coordinate axes Xc are orthogonal to each other.

A camera coordinate system ΣC1 consisting of the Yel axis, the Zc axis, and the Tsumugi axis is set. In this camera coordinate system ΣC1, the Ycl axis is on the optical axis 21, the Xel axis is parallel to the elevation axis 10, and the Z
The cl axis is set to be parallel to the pivot axis 9. Further, the optical axis 21 passes through the center of the two-dimensional position detector 17,
This optical axis 21 and the light receiving surface 19 are perpendicular.

Regarding the optical device 7, three mutually orthogonal coordinate axes Xez wheel, YO2 wheel, and Z
A camera coordinate system ΣC2 consisting of c2 axes is set. This camera coordinate system ΣC2 is set so that the YO2 wheel is on the optical axis 22, the Xcz ring is parallel to the elevation axis 10&, and the Zcz wheel is parallel to the rotation axis 9a. Also, the optical axis 22
passes through the center of the light receiving surface 19a of the two-dimensional position detector 17a and is perpendicular to the light receiving surface 19m. Here, the principal point, T:F, of the lens 18 of the optical device 6 is assumed to be O8, and the principal point of the lens 18a of the optical device 7 is assumed to be 0□.

Optical IW 16. having the configuration as described above. ? , the light source 5 is in the absolute coordinate system Σ. The operation of calculating these coordinate components (xwy*z) at point P in will be described below. The imaging positions Q, Q2 on the two-dimensional position detector 17.17a by the light source 5 are the intersections of the light-receiving surface 19.19a and the virtual straight line passing through the point P and the principal point 0+=Oz, respectively.

Here, the three points P, O, and Q are on the same straight line, so 0 + P = ko + Q +
...(1) holds; when transformed, OP 00 + = k O+ Q +
...(2)(OP -ORl) -(OO+
-OR,)=k O+ Q+...(3) (OP-OR,)-RIO,=kO,Q+...(
4) Here, if we use the camera coordinate system ΣC9 to express the second term on the left side and the right side of Equation 4, we get OP-OR+-T+a+=kT+b+...(s
) However, OP = [xtFvZ]: Absolute coordinate system (6
)OR+= [D 110 to ]': Absolute coordinate system
... (7) a, = EO, ΔF + eO]: Camera coordinate system, ... (8) b + = [Hre F +vV +
];7>/La coordinate system-(9)T.

...(10) ; From camera coordinate system ΣC1 to absolute coordinate system Σ. transformation matrix to F, ; Intersection R with the principal point O8 of the optical device 6.

Distance between the principal point 01 of the optical device 6 and the light-receiving surface 19 ΔF, where the displacement angle θ1. The reference state for this is that the optical axis 21 is Y
This is the case when the displacement is parallel to the axis, and the direction of the arrow in FIG. 4 is taken as the positive displacement direction. The reference state regarding the displacement angle θI2 is the optical axis 21
is on the XY plane, and the direction of the arrow in FIG. 4 is taken as the positive displacement direction.

Since the three points P-02-Q2 are also on the same straight line, similarly, 0P-OR2-Ta,=kTb2...(11)
However, op = [x*ytzl −(
12) OR2= [D t, Oto ]L
...(13) a2°[0! ΔF,,01'
-(14)bz= [)(z*-F 21V 2]
t"' (15) ■... (16); Transformation matrix F2 from camera coordinate system ΣC2 to absolute coordinate system Σ.; Distance ΔF1 between principal point 0□ of optical device 7 and intersection R2; Optical device 7 The reference state for the displacement angle θ2, which is the distance between the principal point 0□ and the light-receiving surface 19a, is when the optical axis 22 is parallel to the Y-axis, and the direction of the arrow in FIG. The reference state regarding the displacement angle θ22 is
This is a case where the optical axis 22 is on the XY plane, and the direction of the arrow in figure #44 is taken as the positive displacement direction.

Here, from the fifth equation, x-B + = kA + ""
(17)y-B,=kA2・
...(18)z−B −= kA s
”' (19)...(20) However, AI = 609 θth H, +sin θ
1leO3θ 12F l + sinθ11s
inθ,,V, ・(21)A2
= sinθ++H+ −C09thθ eosθ+zFI=
Cos θ eye sin θ eye V word...(22)
A, = -5inθ 12FI
+cosθ Goose 2V,
, (23)B,
=D −5inθ l, eO8θ 12
ΔF1...(24) 13, == cose lIC0
5012ΔF.

...(25) 13, = sin
θ12ΔF.

...(26) Also, from the 11th equation, x B , = kA −・= (27) y−BS=k
A5...(28)z B s
= kA s - (29)...(
30) However, A, = cose t+ H2+ sinθ21eo
sθ12F2+sinθ 21sinθ 2□■2
...(31)A5=sinθ
z+Ht-eosθ 21cO9θ 22F2 e
O8θ 21g! nθ zzV t
−(32)A, = −5inθz2
Fz+eosθ22■2-...(33) B4=D2-5inθ2+cos19
22ΔF2...(34) 13s= eoliθ 21co
sθ 22ΔF2...(35) B a= sinθ 22ΔF2
・ (36) #& When formula 20 and formula 30 are completed and solved, A, B2+A, AiB4-A, A4Bri...(
37) 10A, A, B 2+ A zA sB 4- A
2A, BS...(38) + A 4 (B 2 - BS)] + 83
...(39) is obtained.

FIG. 5 is a block diagram showing the overall configuration of the present invention.

The two-dimensional position detector 17 has two electrodes 23, 2 that form a pair.
4; realized as a photodiode, for example, containing 25.2G. The two-dimensional position detector 17a is also realized as a photodiode including two pairs of electrodes 27, 28: 29, 30. Here, the current generated by the incident light from the light source 5 (see FIG. 1) focused on the imaging position Q1 of the two-dimensional position detector 17 is transmitted to the electrodes 23 and 2.
4:25.26, respectively, and the current Il
It is derived as l~I14. The current outputs 112 to r+< of the electrodes 23 to 26 are provided to a processing circuit 31, which is a second calculation means and is realized by, for example, a microcomputer.

Here, the coordinates (H, , Vl) of the imaging position Q1 are determined by the following equations 40 and 41.

The above equations 40 and 41 are calculated by the processing circuit 31 realized by, for example, a microcomputer, and inputted to the motor drive circuit 32, 33 and the calculation i-8 which is the second calculation means. Motor drive circuit 3
2.33 is the coordinate value (H,,V,) of the imaging position Q1
The motors 11 and 13 are driven to rotate the rotation axis 9 and the elevation axis 10 so that the origin of the camera coordinate Σc1 moves in a direction to make each zero, that is, toward the imaging position Q1. This rotation angle θ93. θ1□ is rotation angle detector 1
5.16 and input to the arithmetic unit 8.

On the other hand, the two-dimensional position detector 17a also performs the same operation,
Each electrode 27, 28: Output current from 29, 30 2□
~I24 is output to the processing circuit 31, and corresponding to this current value, the light source 5 (first
Image formation position of incident light from (see figure)! Coordinates of Q2 (I2.V
A signal representing l) is sent from the processing circuit 31 to the motor drive circuit 3.
4.35 and arithmetic unit W18. The motor drive circuits 34.35 perform operations similar to those of the motor drive circuits 32.33 described above [therefore, the rotation angles detected by the rotation angle detectors 15a, 16a of the rotation axis 9a and the elevation axis 10a are , respectively θ21. Let θ2□.

These signals are also given to the arithmetic unit 8.

In the computing device g1B, the coordinates (I2°V
z) in the 40th formula and #41 formula, the variable I
Calculate by formulas in which II to T I4 are replaced with variables ■2□ to rz<, respectively. Therefore, the arithmetic unit 8 calculates the data PHITV l? based on the 37th to 39th equations, the 40th equation, and the 41st equation. H2IV 21190
Lightning θ12. θ2. ．． From θ2□, the coordinates of light source 5 (X+F
eZ) can be calculated.

In this calculation operation, the imaging position Qlt Q2 is
．． 19a, that is, the camera coordinate system ΣelfΣc2
The ball will be hit in the same way even if it is located at the origin of the ball or if it is located at a different position from the origin.

As described above, in the measuring device 1 according to the present invention, the robot 2
Even for objects to be measured that move at high speed in space, such as the arm 3 of the robot, by tracking the point to be measured 4, it is possible to measure the object over a wide spatial area. Therefore, in the present invention, the object to be measured does not fall out of the field of view of the optical VCC positions 6 and 7.

In addition, measurement can be performed simply by attaching a light source 5 such as a light emitting diode to the measurement point 4, so when measuring the object to be measured, the conventional measuring device
As shown in FIG.

In addition, the rotation angle detector 15.1, which is realized by an encoder or the like, does not impose any load or hindrance on the movement of the object to be measured because the measurement is performed without contact using light.
In step 6, by using a high-resolution detector, the three-dimensional position of the detected object can be measured with high precision.

The configuration for realizing the present invention is not limited to the configuration described in the above-described embodiments, but can be realized by a wide range of other components. That is, the absolute coordinate system Σ. The camera coordinate system ΣcltΣc2 is not limited to an orthogonal coordinate system.

Further, the supporting means is not limited to a so-called non-pulsating structure, and a wide range of structures can be used in which the optical axes 21.degree. 22 of the optical devices 6, 7 can be set in any desired direction.

Effects As described above, according to the present invention, a light source is attached to the object to be measured, and an optical detection means to which light from the light source enters is provided.

The optical detection means includes a light receiving element and an optical system that forms an image of the light from the light source on the light receiving surface of the light receiving element.

This optical detection means is supported by means for supporting it so that it can be displaced with respect to two mutually intersecting axes, and each position of the optical detection means on the two axes is detected by the position detection means. Also provided is a first calculation means for driving an optical detection means by the supporting means based on an output signal of the light receiving element to form an image of the light source on a predetermined position on the light receiving surface, and second calculating means for calculating the three-dimensional position of the light source based on the outputs of the position detecting means and the position detecting means.

Therefore, according to the present invention, as the object to be measured moves, the optical detection means always tracks the light from the light source so that it is incident on the light receiving surface, and the optical detection means uses the light to non-contact. Therefore, the measurement operation does not interfere with the movement of the object to be measured, and the position of the object to be measured can be measured over a wide range of space. The three-dimensional position of the object to be measured is calculated by the calculation means based on outputs from the position detection means and the light receiving element.

Therefore, by setting the resolution of the position detection means to a desired level, it is possible to set the measurement accuracy of the obtained three-dimensional position of the object to be measured to a desired level.

[Brief explanation of drawings]

Figure #41 is a simplified system diagram of the measuring device 1 according to an embodiment of the present invention, Figure 2 is a perspective view of optical wave RA4, Figure 3 is a perspective view of optical fif 114, and Figure 4 is a detailed diagram of the present invention. FIG. 5 is a block diagram showing the overall configuration of this embodiment. 1... Measuring device, 3... Arm, 4... Point to be measured,
5... Light source, 6.7... Optical device, 8... Arithmetic device, 9.9a... Rotating axis, 10.10a... Elevation axis, 11, 11a, 13.13a... Motor, 14,1
4a...Optical tube, 15°15a=16,16a...
Rotation angle detector, 17.17a... two-dimensional position detector,
18... Lens, 19... Light receiving surface, 31... Processing circuit

Claims (1)

[Scope of Claims] A light source attached to an object to be measured; and an optical detection means, which forms an image of the light source and derives a signal representing the imaged position.
such an optical detection means including a dimensional light-receiving element, an optical system that is provided integrally with the light-receiving element and forms an image of the light source on the light-receiving surface of the light-receiving element; means for supporting the optical detection means so as to be displaceable about two axes; means for detecting each position of the optical detection means on the two axes; and means for detecting the positions of the optical detection means on the two axes; a first calculating means for driving an image of the light source to form an image of the light source at a predetermined position on a light receiving surface; and a second calculating means for calculating a three-dimensional position of the light source based on the outputs of the light receiving element and the position detecting means. What is claimed is: 1. An optical three-dimensional position measuring device comprising: calculation means.